The display of information via electroluminescent panels is a known concept. C. Suzuki et al are authors of two articles that appear on pages 50-53 of the SID 1976 Digest which are titled: "Character Display using Thin-Film EL Panel with Inherent Memory" and "Optical Writing on a Thin-Film EL Panel with Inherent Memory." The first article covers the concept of providing a grid matrix of conductive members in combination with a thin-film electroluminescent panel which will display information in accordance with the selective operation of the conductive members when writing pulses are applied thereto. This information will be stored due to the application of sustaining pulses to the stored information and erasure occurs when erase pulses are applied to the conductive members. The second article is directed to the use of light to write and store information on an electroluminescent panel of the type disclosed in the first article.
U.S. Pat. No. 3,896,328 to Potter discloses a cathode ray tube that uses a dual phosphor screen which compries a phosphor target on the inside surface of a glass faceplate and a photoluminescent panel constructed of a layer of photoconductive material and a layer of electroluminescent material is placed on the outside surface of the faceplate. This structure will not store information that has been visibly displayed.
U.S. Pat. No. 3,344,300 to Lehrer et al covers the concept of applying an electron beam of a cathode ray tube to a field-sustained conductivity layer thereby increasing conductivity of areas engaged by the electron beam and voltage applied across an electroluminescent layer adjacent the field-sustained conductivity layer will be increased and luminance will occur at locations of the electroluminescent layer corresponding to electron beam-activated areas of the field-sustained conductivity layer to display such information. No storage of this displayed information will take place either. Conventional storage cathode ray tubes are also known but these require flood guns, their contrast ratio is not very high, brightness of displayed information is a problem and operating life is not as long as desired.